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U.  S.  DEPARTMENT  OF  AGRICU 


BUREAU  OF  ANIMAL  INDUSTRY.— BuLLETl 


A.  D.  MELVIN,  CH.EH  of  Bureau.       ^  ||^  j^/j^f^    ^  g-  \^'^^   gj 


bXPERIMENTS  WITH  MILK  ARTIFICIALLY 
INFECTED  WITH  TUBERCLE  BACILLI. 


E.  C.  SCHROEDER,  M.  D.  V., 

Superintendent  of  Experiment  Station, 
Bureau  of  Animal  Industry, 

AND 

W.   E.  COTTON, 

Expert  Assistf7tt  at  Experiment  Station, 
Bureau  of  Anitnal  Industry. 


-t' 


f  California 

Regional 

F'acility 


WASHINGTON: 

GOVERNMENT    PRINTING   OFFICE. 
1906. 


%^^'^ 


"V^. 

"-^i*. 


ORGANIZATION  OF  THE  BUREAU  OF  ANIMAL  INDUSTRY. 


Chief:  A.  D.  Melvin. 

Assistant  Chief:  A.  M.  Farrington. 

Chief  Clerk:  E.  B.  Jones. 

Dairy  Division:  Ed.  H.  Webster,  chief;  Clarence  B.  Lane,  assistant  chief. 

Inspection  Division:  Kice  P.  Stedix>m,  cliief ;  Morris  Wooden,  assistant  chief. 

Quarantine  Divisixm:  Richard  W,  Hickman,  chief. 

Animal  Husbandman:  George  M.  Rommel. 

Editor:  James  M.  Pickens. 

Artist:  W,  S.  D.  Haines. 

Librarian:  Beatrice  C.  Oberlv. 

laboratories. 

Biochemic  Division:  Marion  Dorset,  chief. 

Pathological  Division:  John  R.  Mohler,  chief. 

Zoological  Division:  Brayton  H.  Ransom,  scientific  assistant  in  charge. 

experiment  station. 
E.  C.  Schroeder,  superintendent ;  W.  E.  Cotton,  assistant. 


meat   fNSPECTION. 

Inspectors  in  charge. 


Austin,  Minn. — Dr.  M.  O.  Anderson,  care  George 

A.  Ilormel  &  Co. 
Baltimore,  Md.— Dr.  H.  A.  lledrick,  215  St.  Paul 

street. 
Bloomington,  111. — Dr.  Frederick  Braginton,  cara- 

Continental  Packing  Company. 
Boston,  Mass. — Dr.  J.  F.  Ryder,  141  Milk  street. 
Brightwood,    Mass.— Dr.    W.    J.   Murphy,   care 

Springfield  Provision  Company. 
Buffalo,  N.  Y.— Dr.  B.  P.  Wende,  Live  Stock  Ex- 
change Building,  East  Buffalo. 
Cedar  Rapids,  Iowa.— Dr.  T.  A.  Shipley,  care  T.M. 

Sinclair  &  Co. 
Chicago,  111.— Dr.  S.  E.  Bennett,  room  316  Ex- 
change Building,  Union  Stock  Yards. 
Cincinnati,  Ohio. — Dr.  A.  G.  G.  Richardson,  care 

Union  Stock  Yards. 
Cleveland,  Ohio. — Dr.  E.  P.  Schaflter,  care  Cleve- 
land Provision  Company. 
Davenport,  Iowa.— Dr.  E.  L.  Bertram,  care  Henry 

Kohrs  Packing  Company. 
Denver,  Colo.— Dr.  W.  E.  Howe,  care  Western 

Packing  Company. 
Des  Moines,  Iowa.— Dr.  A.  B.  Morse,  care  The 

Agar  Packing  Company. 
Detroit,  Mich.— Dr.  L.  K.  Green,  care  Hammond, 

Standish  &  Co.         ' 
Eau  Clairo.  Wis.— Dr.  G.  W.  Butlei,  care  Drtun- 

mond  Brothers. 
Fort  Worth,  Tex.— Dr.  A.  H.  Wallace,  care  Swift 

&Co. 
Hutchinson,   Kans.— Dr.  J.   E;  Blackwell,  care 

Hutchinson  Packing  Company. 
Indianapolis,  Ind.— Dr.  N.  C.  Sorensen,  care  Kiu- 

gan  &  Co. 
Jersey  City,  N.  J.— Dr.  Julius  Huelsen,  care  The 

Jersey  City  Stock  Yard  Company. 
Kansa-s  City,  Kans.— Dr.  L.  R.  Baker,  room  338 

Live  Stock  Exchange. 
Los  .\ngelos,  Cal.— Dr.  .\.  E.  Rishel,  care  Cudahy 

I'acking  Company. 
Louisville,  Ky.— Dr.  H.  II.  George,  507  Johnson 

stre<!t. 
Mankato,  Minn.— Dr.  H.  H.  Dell,  care  Macbeth  & 

GardufT. 
Marshalltown,  Iowa.— Dr.  J.O.  K.  Price, careBrit- 

tain  <fe  Co. 
Mason  City,  Iowa.— Dr.  Robert  Jay,  care  Jacob  E. 

Decker  &.  Sons. 


Milwaukee,  Wis.— Dr.  A.  E.  Behnke,  room  432 

Federal  Building. 
Nashville,  Tenn.— Dr.  W.  B.  Lincoln,  care  Tennes- 
see Packing  and  Provision  Companv. 
National  Stock  Yards,  111.— Dr.  J.  B.  Clancy. 
Nebraska   City,  Ncbr. — Dr.  W.  11.  Gibbs,  care 

Morton-Gregson  Company. 
Newark,  N.  J.— Dr.  Thomas  Castor,  care  Swift  & 

Co.,  Harrison  Station. 
New  Haven,  Conn. — Dr.  Albert  Long,  care  Sperry 

&  Barnes. 
New  York,  N.  Y.— Dr.  H.  N.  Waller,  109  West 

Forty-second  street. 
Ottumwa,  Iowa. — Dr.  Joshua  Miller,  care  John 

Morrell  &  Co. 
Philadelphia,  Pa.— Dr.  C.  A.  Schaufler,  134  South 

Second  street. 
Pittsburg,  Pa.— Dr.  F.W.Ainsworth,  Union  Stock 

Yards. 
Portland,  Oreg. — Dr.  Clarence  Lovebcrry,  room 

402  Custom-House  (new) . 
Quincy,    III.— Dr.  J.  S.   Kelly,    care   Blomer  & 

Michael  Co. 
St.  Louis,  Mo. — Dr.  J.  J. Brougham, care  Missouri 

Stock  Yards  Company. 
San  Diego,  Cal.— Dr.  Robert  Darling,  care  Charles 

8.  Hardy. 
San  Francisco,  Cal.— Dr.  George  S.  Baker,  Sixth 

and  Townsend  streets. 
Seattle,  Wash. — Dr.  O.  B.  Hess,  care  Fryc-Bruhn 

Company. 
Sioux  City,  Iowa. — Dr.  G.  A.  Johnson,  Exchange 

Building. 
South  Omaha,   Ncbr.— Dr.  Don  C.  Ayer,  Post- 

OfRce  building. 
South  St.  Joseph,  Mo.— Dr.  George  Ditewig. 
South  St.  Paul,  Minn.— Dr.  F.  D.  Ketchum. 
Tacoma,  Wash.— Dr.  E.  C.  Joss,  care  Carstens 

Packing  Company. 
Topeka,  Kans.— Dr.  F.  L.  De  Wolf,  care  Charles 

Wolff  Packing  Companv. 
Waterloo,  Iowa.— Dr.  T.  W.  Scott,  care  The  Rath 

Packing  Company. 
Wichita,  Kans.— Dr. W.  N.  Neil,  care  John  Cudahy 

Companv. 
Worcester,  Mass.— Dr.  E.  P.  Dowd,  care  White, 

Pevey  &  Dexter  Co. 


(Concluded  on  p.  3  of  cover.) 


U.  S.  DEPARTMENT   OF  AGRICULTURE, 

BUREAU  OF  ANIMAL  INDUSTRY  .—Bullktin  No.  8o. 

A.   D.   MHIA'IN.  Chihk  oy  Blreau. 


EXPERIMENTS  WITH  MILK  ARTIFICIALLY 
INFECTED  WITH  TUBERCLE  BACILLI. 


E.   C.  SCHROF.DHR.   M.  1).   V., 

Superinteudeui  of  E.\pfii)iu'iti  SI  a  Hon, 
Bureau  of  .■l)ii))ial  hidustry, 

AXIJ 

W.   H.   COTTON. 

Expert  Assistant  at  Iixperijnent  Station, 
Ihtreaii  of  Anijnat  Indiistiy. 


WASHINGTON: 

GOVHRNMHNT    I'RINTING    OFFICE. 


LETTER  OF  TRANSMITTAL. 


U.  S.  Department  of  Agriculture, 

Bt  REAU  OF  Animal  Industry, 

WasU7igto7},  D.  C,  May  19,  1906. 
Sir:  I  have  the  honor  to  transmit  herewith,  and  to  recommend  for 
piibhcation  as  a  bulletin  in  the  series  of  this  Bureau,  a  manuscript 
entitled  "Experiments  with  Milk  Artificially  Infected  with  Tubercle 
Bacilli,"  by  Dr.  E.  C.  Schroeder  and  W.  E.  Cotton,  of  the  Experi- 
ment Station  of  this  Bureau.  The  work  consisted  of  feedino;  and 
inoculation  experiments  with  guinea  pigs  and  hogs,  and  was  under- 
taken to  gain  more  definite  information  concerning  the  danger  of 
contracting  tuberculosis  through  the  ingestion  of  milk  containing 
tubercle  germs. 

This  work  throws  new  light  upon  the  tuberculosis  problem  and  is 
especially  important  in  its  bearing  on  the  sup]>osition  that  the  most 
common  way  of  contracting  the  disease  is  through  the  respiration. 
The  authors  conclude  that  the  great  frequency  of  lung  tuberculosis 
need  not  be  wholly  ascribed  to  that  form  of  exposure,  but  that  the 
lung  may  and  does  become  infected  when  the  bacilli  enter  the  system 
in  other  waj^s.  Special  attention  is  directed  to  the  danger  of  infection 
by  tuberculous  material  taken  into  the  body  with  the  food. 
Respectfully, 

A.  D.  Melvix, 
Chief  of  Bureau. 
Hon.  James  Wilson, 

Secretary  of  Agriculture. 
2 


CONTENTS. 


An  experiment  with  g^iiinea  jiij^s o 

Plan  of  t lie  experiment 5 

The  infectious  material 5 

Methods  of  infeetinsi  the  animals G 

Results  of  feedings  and  inject  ions 6 

The  susceptibility  of  guinea  pigs  to  tuberculosis S 

Distribution  of  lesions  in  the  guinea  pigs 9 

A  subcutaneous-inoculation  experiment  witii  hogs 10 

Hogs  inoculated  with  culture  No.  1 11 

Hogs  inoculated  with  culture  No.  2 , _  11 

Hogs  inoculated  with  culture  No.  3 ......  12 

Hogs  inoculated  with  culture  No.  4. 1 .3 

Distribution  of  lesions  in  the  hogs 13 

Susceptibility  of  the  lung  to  infection  other  than  by  respiration 14 

Tosts  showing  lu)W  the  lung  filters  tlie  blood 15 

Spread  of  infection  to  other  organs IG 

Remarks  on  the  hog  inoculations .  IG 

New  significance  of  lung  infection .  17 

Resistance  of  tubercle  germs IS 

Summary 19 


Digitized  by  the  Internet  Archive 

in  2007  with  funding  from 

IVIicrosoft  Corporation 


http://www.archive.org/details/experimentswithOOschriala 


EXPERIMENTS  WITH  MILK  ARTIFICIALLY  INFECTED 
WITH  TUBERCLE  BACILLI. 


AN  EXPERIMENT   WITH    GUINEA  PIGS. 

Some  of  the  work  done  recently  at  the  Experiment  Station  with  milk 
from  tuberculous  cattle  pive  results  which  indicate  that  the  dan^rer 
of  contracting  tubercidosis  throu<rh  the  in<jestion  of  milk,  while  it  does 
exist  and  should  be  guarded  agauist,  is  of  secondary  importance  com- 
pared with  other  modes  of  infection.  In  order  to  gain  more  definite 
information  on  the  su])ject,  an  experiment  was  made  in  which  a  num- 
ber of  guinea  pigs  were  exposed  to  infection  with  tubercidosis  through 
milk  from  normal,  healthy  cows  to  which  cultures  of  tubercle  bacilli 
had  been  added.     A  detailed  account  of  the  experiment  follows. 

PLAX    OF    THE    EXPERIMENT. 

THE    IXFECTIOrS    MATEKIAI.. 

A  virulent  culture  of  tubercle  bacilli  on  agar  was  obtained  from  the 
Pathological  Division  of  this  Bureau,  and  a  portion  of  the  surface 
growth  was  scraped  ofl'  and  suspended  in  sterile  water.  TIk^  watery 
suspension  contained  a  sufficient  amount  of  infectious  material  in  a 
finely  divided  state  to  give  it  a  homogeneous,  well-marked,  cloudy 
appearance.  As  much  material  as  would  cling  to  a  fine  j)latimiin  wire 
loop — the  wire  about  one-fourth  nun.  and  the  loop  al)out  2  mm.  in 
diameter — was  transferred  from  the  susj^ension  to  fresh  normal 
milk  at  the  rate  of  one  loop  per  10  c.  c.  of  milk,  and  this  milk  was  desig- 
nated "  Infection,  degree  A. "  From  the  original  watery  suspension  one 
loop  of  material  was  added  to  10  c.  c.  of  sterile  water  and  material  from 
the  sterile  water  to  fresh,normal  milk  at  the  rate  of  one  loop  per  1 0  c.  c. 
of  milk,  and  this  milk  was  designated  "Infection,  degree  B."  Again, 
from  the  original  watery  suspension  one  loop  of  material  was  added 
to  100  c.  c.  of  sterile  water  and  material  from  the  sterile  water  added 
to  fresh  normal  luilk  at  the  rate  of  one  loo]i  ])er  10  c.  c.  of  milk,  and 
this  milk  was  designated  "  Infection,  degree  C." 

During  the  experiment  four  sej)arate  agar  cultures  of  tubercle 
bacilli  were  used,  all  strongly  virulent  for  guinea  pigs,  and  all  made 
from  the  same  stock  culture  in  the  Pathological  Division.     T\\v  cul- 


6  EXPERIMENTS    WITH    INFECTED    MILK. 

tiires  were  30  days  old  at  the  time  they  were  used,  and  were  received 
at  this  station  on  the  followino;  dates,  one  cidtiire  on  each  day:  July 
1.3,  July  21 ,  July  27,  and  Auijust  9.  The  suspension  of  tubercle  bacilli 
in  water  obtained  from  each  culture  was  used  daily  to  infect  the  milk, 
as  before  described,  until  a  fresh  culture  was  received,  when  a  fresh 
watery  suspension  was  made  and  the  old  one  discarded. 

METHODS    OF    INFECTING    THE    ANIMALS. 

Milk  of  each  of  the  three  decrees  of  infectiousness  was  used  for 
injectino;  and  feeding,  some  of  the  guinea  pigs  l)eing  injected,  intra- 
abdominally,  some  fed  one  day,  and  some  fed  thirty  days. 

Before  the  feeding  was  begun  the  guinea  pigs  were  deprived  of  food 
and  drink  for  a  period  of  twenty-four  hours  in  order  to  induce  them  to 
take  a  large  qiumtity  of  the  infected  milk.  The  guinea  pigs  fed  one 
day  received  nothing  l)ut  infected  milk  after  the  period  of  starvation 
until  they  had  each  consumed  50  c.  c,  and  the  guinea  ])igs  fed  thirty 
days  were  deprived  of  all  drink  ])ut  infected  milk  during  the  whole 
period  and  consumed  an  average  of  60  c.  c.  each  per  day.  The  average 
daily  amount  of  milk  taken  by  the  30-day  guinea  pigs  is  large,  l)ecause 
the  little  animals  soon  learn  to  like  milk  very  nmch  and  then  drink  it 
eagerly  the  moment  it  is  placed  before  them. 

The  amount  of  infected  milk  used  for  injecting  was  5  c.c.  for  each 
guinea  pig. 

Cover-glass  preparations  from  milk  of  "  Infection,  degrees  B  and  C," 
were  examined  under  the  microscope,  and  the  number  of  bacilli  in  the 
same  was  found  to  be  too  small  for  their  detection,  even  when  the 
cover  glasses  were  prepared  from  the  sediment  in  the  bottoms  of 
tubes.  The  latter  were  of  15  c.  c.  capacity  and  had  l)een  rotated  in  a 
centrifugal  nuichine  for  half  an  hour  at  the  rate  of  2,000  revolutions 
per  minute. 

RESULTS    OF    FEP:DINGS    AND    INJECTIONS. 

The  results  obtained  from  the  feedings  antl  injections  are  shown  in 
the  accompanying  tables. 


RESULTS    OF    FEEDING    AND    INJECTING    Gl^INEA    PIGS.  ( 

Table  I. — Results  of  injections  and  feedinqs  of  milk  ''Infection,  deijrce  A"  (1  loop  of  cloudy 
suspension  in  xvatei'  of  tubercle  bacilli  per  each  10  c.c.  of  milk). 


^."Inop     Injected 
e^n^**     or  fed. 
pig- 


Date  of  feed- 
ing or  injec- 
tion. 


Total 
amount 
received. 


Date  of  death . 


Autopsy. 


005;{ 

(i()54 

(i079 

0080 

0101 

0102 

0119 

0120 

6025 

Ga26 

0027 

0028 

6029 

60:50a 

0133    . 

6134    . 

013.1    . 

6130    . 

6137    . 

61. -'S    . 

0013    . 

G014  !. 
6015«  . 

6016  . 

6017  . 

6018  . 


Injected    July  13,  1905 

...do do 

...do July  21,  1905 

.  ..do do 

...do Julv  2<»,  1905 

...do .'do 

...do .\ug.  9,  1905 

...do do 

Fed July  13,  1905 


do. 
...do... 
...do... 
...do... 
...do... 
...do... 
...do... 
...do... 
...■lo... 
...do... 
...do... 
...do... 

..do... 
..do... 
..do... 
..do... 
..do... 


.do. 

.do. 

.do. 

.do. 

do 

.Vug.  11,  1905 

do 

do 

do 

do 

do 

July     13     to 
-Vug.  12,1905 

do 

do 

do 

do 

do 


c.  c. 

5  Died  .Vug.  7,  1905.  . .  Generalized  tulxrculo.sis. 

5  Died  .Vug.  5.  li»05...            Do 

5  Died  -Vug.  10,  l.tOo.  .            Do. 

5  Died  .Vug.  15.  1905.  .            Do. 

5  Died  Sept.  5,  1905...            Do. 

5  Died  Sept.  8,  1905...            Do. 

5  Died  .Vug.  31,  1905.  .            Do. 

5  Died  Sept.  S.  KtOo...            Do. 

.■)()  Killed  Oct.  21.  1905..  No  lesions  of  di.sease. 

.tO    do Do. 

50    do GinxTiilized  tuberculosis. 

50    do No  lesions  of  disease. 

50    do Do. 

50    do '  Do. 

.50  Killed  Oct.  25,  1<K)5..            Do. 

.V)    do Extensive  tulterculosis. 

50    do No  lesions  of  disense. 

■fO    do Do. 

.50    do E.xtensive  tulx'rculosis. 

50    do Do. 

1,800  Died  Sept.  13.  1905..  Generalized  tuberculosis. 

1.800  i  Killed  Oct.  19,  1905..  Extensive  tuberculosis. 

1,800    do ;  Do. 

1,800  I do Do. 

1.800  ' do Do. 

1,800    do Do. 


a  Guinea  pigs  Nos.  (i015  and  0030  each  produced  two  young  during  the  experiment,  which  on  autopsy 
were  found  to  be  free  from  disease. 

T.vBLE  II. — Results  of  injections  and  feedings  of  milk  "Infection,  degree  B''  (1  loop  of  cloudy 
suspension  in  water  of  tubercle  bacilli  to  10  c.  c.  of  sterile  water  and  1  loop  of  the  latter  per  each 
10  c.  c.  of  milk). 


^r'"^'- 


0051 

0O52 

0077 

0078 

0099 

0100 

0117 

0118 

0031 

0032 

0a53 

(i034 

6035 

603ti 

6127 

6128 

61'29 

6130 

0131'' 

01.32 

(i043 


0044 
0045 
f)040 
6047 
6048 


...do 
...do 
...do 
...do 

Fed. 
...do 
...do 

..do 
...do 
...do 


Date  of  in- 
jection or 
feeding. 


ted 

Julv  13,  1905 

do 

Julv  21,  1905 

do 

Julv  2<).  U)05 

do 

.Vug.    9,  1905 

do 

Julv  13,  1905 
:do 

do 

do 

do 

do 

-Vug.  11,  1905 

.....do 

do 

do 

do 

do 

Julv     13     to 

-Vug.  12.1905 
..     .do 

do 

do 

do 

do 

Total 
amount 
received. 


.50 
,50 
.50 
50 
.50 
.50 
.50 
,50 
,50 
50 
50 
.tO 
1,800 


Diite  of  death. 


Died  Sept.  27,  1905.. 

Killed  Oct.  21.  1..05.. 

Died  Sept.  7,  1905... 

Killed  Oct.  21,  190.5.. 
do 

....do 

do 

do 

Killed  Oct.  20,  l',K)5.. 

Died  .lulv  15,  UK)5.  . 

Killed  Oct.  20,  i;»0.5. 
do 

Died  .Vug.  14.  1905.  . 

Killed  Oct.  20,  liKW.. 

Killed  Oct.  2.5,  IWo.. 

do 

do 


do . 


Killed  Oct.  2r),  1<k), 
...   .do 


l.HOO 
1,800 
1,800 

1.800  d<: 

1.800  do. 


-Vutopsy. 


Generalized  tuberculosis. 
Do. 
D<i. 
Do. 
D.I. 
Do. 
Do. 


No 
I'ne 
No 


Do. 

esions  of  dis 
lunonia. 
esions  of  dis 


'ase. 


Inflanuuiition  of  liowels 
No  lesions  o(  di-sease. 

Do. 

Do. 

Do. 

Do. 


Do. 
Do. 

Do 
D(i 
Do 
Do 
Do 


a  One  young  produced  in  pen,  which  on  autopsy  showed  no  lesions  of  disease. 


EXPERIMENTS    WITH    INFECTED    MILK. 


Table  III. — Results  of  injections  amlfeedings  of  milk''  Infection,  deoreeC"  (1  loop  of  cloudy 
suspension  in  uyiter  of  tubercle  bacilli  to  100  c.  c.  of  sterile  water  ami  1  loop  of  the  latter  per 
each  10  c.  r.  of  milk.) 


No.  of 

Injoetod 
or  fed. 

DatP  of  in- 

Total 

guinoji 

jivtion  or 

amount 

Dato  of  death. 

.Vutopsv. 

pig- 

feeding. 

rccpivod. 

6049 

1  njpctiHl. 

July  i:!,  1905 

f .  c. 
5 

Killed  Oct  21,  1905.. 

Extensive  tul)erculosis. 

6050 

...do.... 

....."do 

5 

Died  Oct.  5,  1905 

Generalized  tiil)erculosis. 

607S 

...do.... 

July  21,  1905 

0 

Died  Oct.  2,  1905... 

Do. 

6076 

...do.... 

do.. 

5 

Killed  Oct.  21,  1905.. 

Extensive  tulKTCulosis. 

(i097 

...do.... 

July  29.  1905 

5 

do 

Do. 

6098 

...do.... 

do 

5 

do 

Do. 

6115 

...do 

.Vug.    9.  1905 

5 

do 

Slight  tulKTCulosis.n 

6116 

...do.... 

do 

5 

do 

Extensive  tu))(>rculosis. 

(«19 

Fed 

.lulv  1:5,  1905 

50 

do 

No  lesions  of  disease. 

(5020 

...do.... 

do 

50 

do 

Do. 

6021 

...do.... 
...do 

do 

do 

50 
50 

..     .do 

Do. 
Do. 

6022 

do 

WXi 

...do.... 

do 

50 

do 

Do. 

(i024 

...do.... 

do 

50 

do 

Do. 

6121 

...do 

-Vug.  11,  1905 

50 

Killed  Oct.  25,  190.5.. 

Do. 

6122 

...do 

do 

.50 

do 

Do. 

612.i 

...do.... 

do 

50 

do 

Do. 

6124 

...do.... 

do 

50 

do 

Do. 

6125 

...do.... 

do 

.50 

do 

Do. 

6126 

.do 

do 

.50 
1,800 

do 

Killed  Oct.  19,1905.. 

Do. 
Do. 

im: 

...do.... 

Julv     i:i     to 

Aug.  12.1905 

6038 

...do.... 

do 

1,800 

do 

Do. 

60:» 

...do.... 

do 

1,800 

do 

Do. 

6040t 

...do.... 

do 

1,800 

do 

Do. 

(i041 

...do 

do 

1,800 

do 

Do. 

6042 

...do.... 

do 

1,800 

do 

Do. 

n  Tuljcrculosis  limited  to  one  gland  near  stomach. 

b  Two  young  produced  in  pen,  which  on  autopsy  showed  no  lesions  of  disease. 

An  examination  of  the  tables  shows  that  all  the  <i;iiinea  pi*;s  injected 
with  the  infected  milk  contracted  tuberculosis,  and  hence  that  every 
5  c.  c.  of  the  milk  at  all  de^^rees  of  infectiousness  actually  contained  live, 
virulent  tubercle  bacilli. 

Of  the  o;uinea  pifjs  that  were  fed  the  milk  which  contained  the  laro;- 
est  amount  of  infectious  material,  100  per  cent  of  those  fed  thirty 
days  and  33J  per  cent  of  those  fed  one  day  l)ecame  affected  with  tuber- 
culosis, showing  conclusively  that  the  particular  tubercle  culture  used 
to  infect  the  milk  possessed  a  sulRcient  deo;ree  of  patho<^enic  viridence 
to  cause  tuberculosis  in  fjuinea  pifjs  throufjh  in<>:estion. 

THE    SUSCEPTIBILITY    OF    OriXEA    PIGS    TO    Tl'BERCI'LOSLS. 

Milk  of  deo;rees  of  infectiousness  B  and  C  failed  to  produce  tubercu- 
losis in  a  sinp;le  guinea  pig  fed  with  it ;  the  12  that  were  fed  thirty  days 
and  consumed  each  a  total  of  1,800  c.  c.  escaped,  as  well  as  those  fed 
only  a  single  day  with  50  c.  c.  each.  The  amount  of  infectious  material 
in  the  milk  was  of  course  very  much  less  than  in  milk  A,  but  it  was 
also  pr<)])ably  very  much  greater  than  the  amount  ])resent  in  naturally 
infected  milk  from  tuberculous  cows  whose  lulders  are  not  affected. 
In  our  experience  with  milk  from  tuberculous  cows  we  have  never 
f(nind  a  cow  with  a  healthy  udder,  no  matter  how  extensiv(>ly  she  was 
othervvi.se  afr(>cted  with  tu])erculosis,  whose  milk,  on  intraalxiominal 
injection  of  guinea  ])igs,  produced   tuberculosis  with   the  regularity 


DISTRIBUTION    OF    LESIONS    IN    GUINEA    PIGS.  9 

and  certaintj^  of  our  artificially  infected  milk.  From  this  we  may 
conclude  that  the  milk  feedino;  practiced  in  this  experiment  consti- 
tutes quite  a  severe  test  of  the  dantjer  encountered  by  fjiunea  pifjs 
through  the  ingestion  of  milk  from  tuberculous  cows  whose  udders  are 
unaffected.  Hence  it  follows  that  the  ingestion  by  guinea  pigs  of 
milk  from  tuberculous  cows  is  a  very  unsatisfactory  test  for  the  })res- 
ence  of  tubercle  bacilli.  This  is  surprising  to  us,  because  of  the  com- 
monly existing  belief  that  guinea  pigs  are  extremely  susceptible  to 
tuberculosis,  irrespective  of  the  manner  in  which  they  are  exposed  to 
the  infection. 

Unfortunately  no  conclusion  can  be  drawn  from  the  results  obtained 
with  the  fed  guinea  pigs  of  the  danger  encountered  by  man  through 
the  use  of  milk  from  tuberculous  cattle,  and  the  failure  of  the  guinea 
pigs  to  contract  tuberculosis  after  swallowing  innumerable  tubercle 
bacilli  suspended  in  milk  shoidd  not  be  construed  as  an  encouragement 
to  use  the  milk  of  a  cow  which  is  known  or  even  suspected  to  be 
affected  with  tuberculosis.  Intestinal  tuberculosis  of  guinea  pigs  is  a 
very  rare  occurrence,  even  when  they  are  affected  with  otherwise 
generalized  tuberculous  disease  and  every  other  organ  is  practically 
saturated  with  tuberculous  material.  It  may  be  that  some  pecul- 
iarity exists  about  the  stomach  and  intestine  of  a  guinea  pig  that 
allows  the  bacilli  of  tuberculosis  to  pass  through  and  out  of  the  body 
more  freely  than  through  the  intestines  of  other  species  of  animals, 
including  man.  This  view  is  strengthened  by  results  recently  o])tained 
in  some  hog-feeding  experiments  at  this  station  in  cooperation  with 
the  Pathological  Division,  which  will  be  reported  in  due  time.  At 
this  time  it  is  sufficient  to  say  that  the  hogs  in  question,  on  exposure 
similar  to  and  no  more  severe  than  that  received  by.  the  guinea  pigs, 
readily  became  affected  with  tuberculosis. 

DISTRIBUTION    OF    LESIONS    IN    THE    GUINEA    PIGS. 

The  location  of  the  lesions  found  on  post-mortem  examination  of 
the  10  guinea  pigs  that  contracted  tuberculosis  through  the  ingestion 
of  infected  milk  warrants  a  few  general  remarks.  A  complete  autopsy 
record  of  each  guinea  pig  is  not  retjuired.  The  following  ta])le  shows 
the  distribution  of  the  lesions  in  each  animal.  Taking  the  number 
9  to  represent  the  total  amount  of  disease  found  in  each  guinea  j)ig, 
the  numerals  in  the  ta])le  rej)resent  approximately  the  amount  of  dis- 
ease found  in  the  several  organs.  The  highest  numeral  in  connection 
with  any  guinea  pig  not  only  indicates  that  the  oriran  luider  which  it 
is  placed  showed  the  most  extensive  tuberculous  changes,  but  that  it 
was,  so  far  as  this  could  be  determined,  the  first  organ  to  l)ecome 
affected.  Aside  from  the  amount  of  disease  in  any  one  organ  as  com- 
pared \\  ith  any  or  all  the  other  organs  in  the  same  animal,  the  munerals 
3 102 1 — N  o.  80— OC 2 


10  EXPERIMENTS    WITH    INFECTED    MILK. 

are  not  intended  to  convey  any  impression  as  to  the  actual  magnitude 
of  the  lesions. 

Table  IV. — Disiribitiion  of  the  lesions  in  10  guinea  pigs  affected  with  tuberculosis  through  the 
imjestion  of  infected  milk. 

^r  ;  Si;  ^^3*  '"■"■  J;»S.  ■•."-  ^p-...  ^!^  ^^  ,„■„,„.. 


pig.       I  glands.      s«w—  e'«""»-  glands. 


glands. 


mis 

1 

1 

(K114 

0 

1 

mia 

2 

2 

(»l(i 

4 

2 

()017 

i 

H 

0018 

3 

1 

1)027 

0 

0 

0134 

1 

0 

0037 

4 

3 

6138 

0 

3 

1   ,          1            1            1            1  1  1 

1    ^             1    !             0    j              i                 i  0  0 

i               1    ,             1    i               i               l"  1  0 

1  0  0 

0                    i  0 

0  0  0 

1    ;          1             1             1             0  0  0 

1                    i                  h                10  0  0 

i             J             i             i           0  0  0 

"10  0 


The  remarkable  fact  about  the  distribution  of  tJie  lesions  in  the 
guinea  pigs  is  that,  notwithstanding  the  entrance  of  the  infection  with 
the  foad,  careful  search  failed  to  discover  lesions  of  the  intestine 
except  in  one  case,  in  which  practically  every  organ  was  affected. 
The  mesenteric  lymph  glands  w^ere  afl'ected  in  only  5  of  the  10  guinea 
pigs,  and  in  no  case  w^ere  the  lesions  of  these  glands  as  important  as 
those  found  in  other  portions  of  the  body  of  the  same  animal.  The 
subcutaneous  glands,  under  which  name  the  glands  in  the  inguinal  and 
axillary  regions  are  included,  were  affected  in  li  animals;  that  is,  more 
frequently  than  the  intestine,  as  the  result  of  ingested  infection, 
although  these  glands  are  in  no  direct  manner  associated  with  the 
organs  of  digestion. 

The  liver  was  affected  in  9  animals,  but  in  no  case  seriously.  The 
portal  glands,  thoracic  glands,  lung,  and  spleen  w^ere  affected  in 
every  guinea  pig;  and  the  throat  glands,  although  entirely  free  from 
determinable  disease  in  2  cases,  were  affected  in  8  cases,  and  4  of  them 
showed  the  most  marked  lesions,  being  probably  the  first  organs 
attacked.  The  animals  which  did  not  show"  the  most  extensive 
lesions  in  the  throat  glands  invariably  showed  the  greatest  amount  of 
disease  in  the  thoracic  glands. 

These  facts  are  interesting  mainly  because  the  infection  of  the 
animals  was  strictly  through  the  food  that  was  eaten  l)y  them.  While 
the  infected  food  had  to  pass  through  the  mouth  and  throat  to  reach 
the  stomach,  its  contact  with  these  parts  was  comparatively  of  short 
durati(m,  and  its  contact  with  the  stomach  and  bowels  of  compara- 
tively long  duration;  therefore  more  extensive  disease  of  the  latter  and 
the  associated  lymph  glands  was  to  be  expected. 

A  SUBCUTANEOUS-INOCULATION  EXPERIMENT  WITH  HOGS. 

"With  reference  to  the  distribution  of  lesions,  the  subcutaneous 
inoculati(»n  of  12  hogs  with  tubercle  bacilli  is  (piite  interesting.  For 
these  inoculations  tubercle  cultures  from  four  different  sources  were 


INOCULATION    OF    HOGS.  11 

used.  All  the  inoculations  were  made  in  the  central  portion  of  the 
ahdominal  region,  immediately  under  the  skin,  just  in  front  of  the 
navel.  The  hogs  used  were  part  of  a  number  that  had  been  previously 
used  in  hog-disease  investigations,  and  were  for  that  reason  unsalable 
and  unserviceable  for  most  other  purposes,  but  there  was  nothing  in 
their  condition  to  unfit  them  for  this  experiment. 

The  tubercle  ciUtures  used  were  obtained  from  the  Pathological 
Division  of  this  Bureau  and  were  as  follows:  (I)  A  culture  isolated 
from  a  human  lung,  third  generation;  (2)  a  culture  isolated  from  the 
lung  of  a  boy,  a  supposedly  bovine-human  culture,  fifteenth  gen- 
eration; (8)  a  culture  isolated  from  the  lung  of  a  hog  that  had  been 
infected  with  bovine  tuberculosis,  twenty-second  generation,  and  (•[)  a 
culture  isolated  from  a  deer,  third  generation.  For  convenience  the 
cultures  will  be  referred  to  as  Xos.  1 ,  2,  3,  and  4. 

The  post-mortem  examinations  of  the  hogs  were  made  with  the  most 
scrupulous  and  searching  care,  and  it  is  doubtful  if  any  lesions,  imless 
they  were  extremely  small  and  well  concealed,  escaped  detection. 
The  autopsy  records  give  all  the  lesions  found  The  presence  of 
tubercle  bacilli  in  every  lesion  about  the  nature  of  which  an}"  doubt 
existed  was  microscopically  demonstrated. 

The  records  of  the  hogs  follow: 

HOGS    INOCULATED    WITH    CI'LTURE    XO.    1. 

Hogs  Nos.  1751,  1790,  and  ISOo  were  each  inoculated  P^ebruary  13, 
1006.  with  a  small  amount  of  the  growth  from  an  agar  culture  of 
tubercle  bacillus  No.  1,  and  were  killed  thirty-seven  dajs  later  and 
examined  post-mortem. 

Autopsy  of  hog  No.  1751:  Weight  at  time  of  death,  59  pounds.  At  the  seat  of  inocula- 
tion is  an  abscess  of  about  5  nun.  diameter,  which  contains  a  dry,  firm,  clieesy  material. 
The  subcutaneous  tissues  surrounding  the  abscess  in  a  band  less  than  'A  nun.  witle  arc 
sprinkled  with  minute  necrotic  foci.  Lung  contains  a  few  small  pearl-like  tubercles.  2  nun. 
and  less  in  diameter,  uniformh  distributed. 

Autopsy  of  hog  No.  1790:  Weight  at  time  of  death,  from  .55  to  (iO  pounds.  .\t  the  seat 
of  the  inoculation  is  an  abscess  about  1  cm.  in  diameter,  the  wall  of  which  is  a  heavy,  dense 
neoplastic  tissue,  inclosing  a  mass  of  dry,  firm,  cheesy  material.  Lung  contains  about  a 
score  of  minute  pearl-like  tubercles,  the  largest  of  which  is  not  more  than 2  mm.  in  diameter. 
Liver  contains  one  small  tubercle  not  more  than  1  nun.  in  diameter. 

•  Autopsy  of  hog  No.  1805:  Weight  at  time  of  death,  (52  pounds.  At  tiio  scat  of  tiie  inocu- 
lation is  an  abscess  in  all  respects  similar  to  that  found  m  the  same  region  in  hog  Xo.  1751. 
Lung  evenly  sprinkled  with  imiumeral)le  pearl-like  tubercles,  whicii  vary  in  size  fiom  mere 
points  to  2  mm.  in  diameter.  Liver  contains  a  few  tulx'rculous  foc-i,  2  nun.  and  less  in 
diameter.  - 

HOGS  ixoci  i..\TEi)  wrrii  ciltuije  xo.  2. 

Hogs  Nos.  1754,  1755,  and  170S  were  each  inoculated  February  13, 
1906,  with  a  small  amoimt  of  growth  from  an  agar  culture  of  ttibercle 
bacillus  Xo.  2,  and  were  killed  thirty-seven  days  later  and  examined 
post-mortem. 


12  EXPERIMENTS    WITH    INFECTED    MILK. 

Autopsy  of  hog  Xo.  1754.  Weight  at  time  of  death,  from  55  to  60  pounds.  At  the  seat  of 
the  inoculation  is  an  abscess  about  1  cm.  in  diameter,  which  contains  a  drj-,  firm,  cheesy 
material.  The  subcutaneous  tissues  surrounding  the  abscess  in  a  band  not  more  than  5  mm. 
wide  are  sprinkled  with  minute  necrotic  foci.  Lung  evenly  sprinkled  with  innumerable 
pearl-like  tubercles,  the  largest  of  which  are  2  mm.  in  diameter.  Liver  contains  a  few 
tubercles  1  mm.  and  less  in  diameter.  Spleen  contains  a  very  small  number  of  tubercles 
from  1  to  2  nun.  in  diameter. 

Autopsy  of  hog  Xo.  1755.  Weight  at  time  of  death,  45  pounds.  Lesions  at  the  seat  of  the 
inoculation  similar  to  that  found  in  hog  No.  1754.  Inguinal  lymph  glands  slightly  enlarged 
and  contain  several  necrotic  tuberculous  areas  from  2  to  3  mm.  in  diameter.  Prescapular 
lymph  glands  slightly  enlarged  and  contain  several  necrotic  tuberculous  areas  from  2  to  3 
mm.  in  diameter,  the  number  of  affected  areas  slightly  greater  than  in  the  inguinal  glands. 
Lung  evenly  sprinkled  with  innumerable  minute  pearl-like  tubercles,  the  largest  of  which 
are  2  mm.  in  diameter.  Bronchial  lymph  glands  enlarged  and  contain  a  small  number  of 
tuberculous  areas.  Liver  evenly  sprinkled  with  innumerable  very  minute  tubercles. 
Portal  lymph  glands  contain  a  small  number  of  minute  tubercles.  Spleen  contains  several 
tubercles  from  1  to  3  nun.  in  diameter. 

Autopsy  of  hog  X'o.  1798.  Weight  at  time  of  death,  62  pounds.  Lesion  at  the  seat  of  the 
inoculation  similar  to  that  found  in  hog  Xo.  1754.  Lung  uniformly  sprinkled  with  numerous 
pearl-like  tuberculous  nodules  from  1  to  2  mm.  in  diameter.  Liver  contains  a  few  minute 
tubercles. 

HOGS    INOCULATED  WITH    CULTURE    XO.  3. 

Hogs  Nos.  1783,  1803,  and  1811  were  each  inoculated  February  13, 
1900,  with  a  small  aiiioant  of  g;rowth  from  an  aojar  culture  of  tubercle 
bacillus  No.  3,  and  were  killed  thirty-eight  days  later  and  examined 
post-mortem. 

Autopsy  of  hog  Xo.  1783.  Weight  at  time  of  death,  55  pounds.  At  the  seat  of  the  inocu- 
lation is  an  abscess  about  1  cm.  in  diameter,  which  contains  a  dry,  firm,  cheesy  material. 
The  subcutaneous  tissues  surrounding  the  abscess  in  a  band  not  more  than  5  mm.  wide  are 
sprinkled  with  minute  necrotic  foci.  Lung  evenly  sprinkled  with  innumerable  minute, 
pearl-like  tubercles  2  mm.  and  less  in  diameter.  Liver  contains  a  considerable  number  of 
very  minute  tubercles.     Portal  h^niph  glands  contain  a  few  veiy  minute  tuberculous  foci. 

Autopsy  of  hog  Xo.  1803.  Weight  at  time  of  death,  52  pounds.  At  the  seat  of  the  inocu- 
lation is  a  lesion  similar  to  that  found  in  hog  Xo.  1783,  but  not  more  than  one-half  as  large. 
Inguinal  lymph  glands  enlarged  and  some  of  them  contain  a  small  number  of  necrotic  areas 
4  mm.  and  less  in  diameter.  Lung  evenly  .sprinkled  with  innumerable  tuberculous  nodules 
from  1  to  4  mm.  in  diameter.  Bronchial  lymph  glands  enlarged  and  thickly  sprinkled  with 
minute  necrotic  foci.  Liver  evenly  sprinkled  with  numerous  tubercles,  the  largest  of  which 
are  3  mm.  in  diameter.  Portal  lymph  glands  enlarged  and  sprinkledj\ith  many  necrotic  foci 
from  1  to  2  mm.  in  diameter.  Spleen  contains  a  few  tuberculous  foci  from  1  to  5  mm.  in 
diameter.  Lymph  glands  at  the  curvature  of  stomach  enlarged  and  sprinkled  with  necrotic 
foci  from  1  to  2  nun.  in  diameter. 

Autopsy  of  hog  Xo.  181 1.  Weight  at  time  of  death,  55  pounds.  At  the  seat  of  the  inocu- 
lation is  a  lesion  similar  in  all  respects  to  that  found  in  hog  Xo.  1783.  One  of  the  inguinal 
lymph  glands  contains  a  few  minute  tuberculous  foci.  Lung  evenly  sprinkled  with  numerous 
pearl-like  tubercles  2  nun.  and  less  in  diameter.  Bronchial  l3-mph  glands  greatly  enlarged 
and  sprinkled  with  tuberculous  foci,  some  of  which  have  a  diameter  of  2  nnn.  Liver  con- 
tains many  tul)ercles  from  1  to  3  mm.  in  diameter.  Portal  lymph  glands  contain  several 
minute  foci  (;f  tuberculosis.  Spleen  contains  several  tuberculous  foci  from  1  to  3  nnn.  in 
diameter. 


DISTRIBUTION    OF    LESIONS    IN    HOGS.  13 

HOGS    INOCULATED    WITH    CULTURE    XO.  4. 

Plogs  Nos.  1772,  1801,  and  1809  were  each  inoculated  Fcbniary  13, 
1906,  with  a  small  amount  of  o;rowth  from  an  at^ar  culture  of  tubercle 
bacillus  No.  4,  and  were  killed  thirty-eight  days  later  and  examined 
post-mortem. 

Autopsy  of  hog  No.  1772.  Wciglit  at  time  of  death,  46  pounds.  At  the  seat  of  the  iuocu- 
lation  is  an  abscess  about  5  mm.  in  diameter,  whieh  contains  a  diy,  firm,  ciieesy  material. 
The  subcutaneous  tissues  surrounding  the  abscess  in  a  band  less  than  3  nun.  wide  are 
sprinkled  with  minute  necrotic  foci.  Lung  contains  many  pearl-like  tubercles  2  nun.  and 
less  in  diameter  located  principally  in  the  apexes  of  the  various  lobes.  Liver  contains  a  few 
small  tubercles,  the  largest  of  which  are  2  nun.  in  diameter. 

Autopsy  of  hog  No.  1801.  Weight  at  time  of  death,  5.5  to  60  pounds.  .\t  tlie  seat  of  tlie 
inoculation  is  a  lesion  similar  to  that  found  in  hog  Xo.  1772,  but  about  twice  as  laige.  Lung 
evenly  sprinkled  with  numerous  tuberculous  nodules  from  1  to  3  nun.  in  diametei'.  Liver 
contains  a  few  very  small  tubercles. 

Autopsy  of  hog  No.  lcS09.  Weight  at  time  of  death.  61  pounds.  .\t  the  seat  of  tlie  inocu- 
lation is  a  lesion  precisely  similar  to  that  found  in  hog  No.  1<S01.  Lung  evenly  sjirinkled 
with  pearl-like  tubercles  from  1  to  2  mm.  in  diameter.    Liver  contains  a  few  minute  tubercles. 

DISTRIBUTIOX    OF    LESIOXS    IX    THE    HOGS. 

In  the  following  table  the  distribution  of  the  lesions  in  each  hog  is 
shown  and  an  attempt  is  made  to  represent  the  ]:)roportionate  amount 
of  the  disease  in  the  affected  organs  b}'  numerals.  It  should  be  stated 
(as  was  the  case  with  the  guinea  pigs  in  Table  TV)  that  tlie  numl)er 
placed  under  each  organ  is  only  intended  to  show  the  proportion  of  the 
disease  in  that  organ  as  compared  with  the  other  organs  of  tlie  indi- 
vidual hog  and  has  no  bearing  on  the  actual  total  amount  of  disease 
present  in  the  hog. 

The  distribution  of  the  disease  in  each  hog  is  estimated  on  a  scale  of 
10.  When  the  number  9,  for  example,  is  placed  in  tlie  lung  column, 
0.75  in  the  liver,  and  0.25  in  the  spleen  column,  it  means  that  the  mag- 
nitude of  the  lesions  in  the  lung  is  nine  times  as  great  as  in  the  liver 
and  spleen  combined — that  is,  9  parts  of  a  total  of  10,  and  the  lesions  in 
the  liver  and  spleen  would  be,  respectively,  0.75  part  and  0.25  ])art 
of  10.  The  table  of  course  is  only  approximately  correct,  because  no 
effort  was  made  to  isolate  and  weigh  and  measure  the  lesions  in  the 
various  organs  of  the  hogs. 

The  last  column  of  the  table  shows  approximately  the  magnitude  of 
the  total  lesions  found  in  each  liog  as  compared  with  any  other  hog. 
In  estimating  the  numbers  given  the  actual  mass  of  the  tuberculous 
tissue  present  in  the  body  was  taken  into  consideration  quite  inde- 
pendent of  its  location  or  distribution,  exce])ting  thht  the  lesions 
found  immediately  at  the  seat  of  th(>  inocculation  were  omitted  from 
the  estimate.  For  example,  if  the  total  lesions  found  in  hog  Xo.  1751 
are  0.1  and  the  total  lesions  found  in  hog  Xo.  1755  are  10  (their 
respective  values  in  the  table)  then  the  actual  relation  of  the  volume 


14 


EXPERIMENTS    WITH    INFECTED    MILK. 


of  lesions  in  the  one  liooj  to  the  other  is  as  0.1  to  10  or  1  to  100.  It  may 
^ive  additional  value  to  the  figures  to  state  that  the  actual  volume  of 
the  tuberculous  tissue  found  in  hog  Xo.  1751  (0.1)  is  equal  to  about 
5  cu.  mm. 

Table  V. — Distribution  of  lesions  in  Jiogs  injected  with  tubercle  cultures. 


i 

No.  1 

of                 Material 
hog.             inoculated. 

Ingui- 
nal 
lymph 
glands. 

Pre- 
scapu- 

la.r 
lymph 
glands. 

Lung. 

10.00 
9.90 
9.<)0 
9.00 
5.00 
9.90 
9.00 
6.00 
5.00 
9.50, 
9.75 
9.50 

Bron- 
chial 
lymph 
glands. 

Liver. 

Portal 

lymph    Spleen. 

g"lands. 

Lymph 

glands  1   Rela- 
ateur-      tive 
vature  amount 
of        of  dis- 
stom-      ease, 
ach. 

]i^,    [Tubercle  bacillus  No. 
1805    1     ^  (hiiiiiiin  lung). 

}'^^    1  Tubercle  bacillus  No. 
j-IS    1     2  (bovine-human). 

]lm   [Tubercle  bacillus  No. 
1811    1     ^  (I'ovine-hog). 

llm    [Tubercle  bacillus  No. 

[ 

'               ' 

0.10 

) 

"6.25' 

"""".25' 
.50 

0.10    

.10 

1.00 

.... 

.1  on 

.75                         0.''5                           5.00 



1    0.25 

0.25 

3.75 

.10 

.75 

2.25 

3.50 

.50 

0.25           .25    10.00 

2.00 

1.    . 

.25                     ...               5.00 

.75 
I       .25 

.25           .25         0.25         10.00 

.25           .50    8.00 

1.00 

.25                   1.00 



1   . 

JiO                                     __.               1.00 

If  we  now  examine  the  autopsy  records  of  the  hogs  as  the}^  are  pre- 
sented in  the  foregoing  table,  we  see  that  tubercle  cultures  Xos.  2  and  3 
are  somewhat  more  virulent  for  hogs  than  cultures  Xos.  1  and  4.  This 
difference  in  virulence  is  not  associated  with  a  tendency  for  the 
lesions  produced  by  any  culture  to  localize  themselves  differently  from 
the  lesions  produced  by  any  other  culture. 

SUSCEPTIBILITY    OF    THE    LUNG    TO    IXFECTIOX    OTHER    TIIAX    BY 

RESPIRATION. 

It  will  be  seen  by  Table  V  that  the  lung  was  in  all  the  hogs  the 
princij^al,  and  very  probably  the  first,  organ  to  become  affected,  and 
this  certainly  could  not  have  been  due  to  the  point  at  which  the 
infectious  material  was  inoculated.  The  point  of  inoculation  was 
s])ecially  selected  to  ])revent  as  far  as  possible  the  more  immediate 
exposure  of  some  one  organ  and  was  located  much  closer  to  the  liver 
and  s])leen  than  to  the  lung.  The  lung  disease  found  was  strictly 
within  the  lung,  some  of  it  imder  ihe  ])idmonary  pleura,  but  not  any 
of  it  on  the  ]>leura  of  either  the  lung  or  the  chest  wall,  and  among  the 
twelve  afl'ected  lungs  only  three  showed  an  affection  of  the  lymph 
glands  associated  with  the  lung  or  contained  within  the  thoracic 
cavity.  This  condition  is  not  regarded  as  showing  a  special  afhnity 
of  tubercle  bacilli  for  the  lung.  It  is  probably  due  to  the  fact  that  the 
tul)ercle  germs  taken  up  from  the  subcutaneous  tissues  successfully 
passed  through  the  lymph  channels  and  various  h^mph  glands  and 
reaclKHJ  the  venous  circulation  and  were  then  filtered  out  by  the  lung. 
Whether  this  view  is  true  or  not  we  have  in  this  experiment  a  demon- 


HOW    THE    LUNG    FILTERS    THE    BLOOD.  15 

stration  of  the  fact  that  the  location  of  the  tuberculous  disease  in  the 
body  is  not  necessarily  a  o:uide  as  to  the  point  at  which  the  infectious 
material  entered. 

TESTS    SHOWIXr,    HOW    THE    LUNC!    FILTERS    THE    BL(K)D. 

The  very  efl'ectiye  manner  in  which  the  luno;  filters  out  solid  par- 
ticles from  the  blood  was  shown  at  the  experiment  station  ])y  the 
injection  into  the  yeins  of  several  animals  of  a  carefully  })re])ared  sus- 
pension in  water  of  pure  lampblack.  While  the  specific  i^ravity  of 
lampblack  is  much  tjreater  than  that  of  water,  in  the  ordinary  form  in 
which  the  dry  sid)stance  can  be  ])urchased  it  is  so  char<i:(Ml  with  air  or 
other  gases  that  it  is  impossible  to  mix  it  with  water.  To  overcome 
this  difficidtv  we  heated  the  lam])])lack  in  a  cruci})le  to  a  red  heat  and 
put  it  into  water  while  hot ,  and  found  that  fully  75  per  cent  of  tlic  mass 
sank  to  the  bottom  at  onco. 

Two  rabbits  were  placed  \mder  the  influence  of  ether  and  1  c.  c.  of  a 
suspension  of  about  10  ])er  cent,  by  weight,  of  lampl)lack  in  water  was 
injected  into  their  ear  veins.  The  result  was  almost  instantaneous 
death.  Two  more  rabbits  without  being  placed  under  the  influence 
of  ether  were  injected  in  the  same  manner  with  the  same  result: 
Ether  was  used  in  the  first  instance  because  it  was  tliought  the  little 
animals  would  suffer  long  and  severely  as  a  residt  of  the  injection.  It 
was  omitted  in  the  second  instance  because  the  operation,  followed  by 
almost  instantaneous  death,  caused  no  more  suffering  than  is  endured 
by  exposure  to  ether  during  the  time  that  pr(>cedes  loss  of  consciousness. 
The  autopsies  of  the  four  rabbits  showed  identical  lesions^a  uniform 
distribution  of  the  injected  lam])l)lack  thi'oughout  the  lungs — and  no 
trace  of  the  intensely  black,  xory  fine,  and  ])ractically  iin])al])able 
powder  in  any  other  ])ortion  of  the  body. 

A  horse  was  also  given  an  intravenous  injection  of  lam])black  sus- 
pension. In  this  case  the  injection  was  made  into  the  jugiUar  xe'in 
and  the  amount  of  material  in  proportion  to  the  weight  of  the  animal 
was  much  smaller  than  that  injected  into  the  rabbits.  The  dose  was 
intentionally  made  small  (50  c.  c.  of  a  1  ]>er  cent  sus])ension)  so  as  not 
to  greatly  affect  the  horse,  which  was  an  old,  vicious  animal,  not 
serviceable  for  other  experimental  purposes  and  not  safe  for  ordinary 
work.  The  actual  amount  of  lamjjblack  introduced  into  the  circula- 
tion of  each  rabbit  was  100  milligrams  (1  ,\  grains)  and  into  the  horse 
500  milligrams  (Tfl  grains).  As  the  liorse  weighed  al)oiit  five  hun- 
dred times  as  much  as  each  rabbit  the  dose  it  receiv(Hl  per  weight  of 
animal  was  one  one-hundredth  of  that  received  by  the  rabi)its. 

The  only  ante-mortem  effect  of  the  injection  into  the  horse  was  an 
increased  rapidity  of  the  respiration,  which  lasted  several  liours  and 
then  subsided.  About  a  week  after  the  injection  the  horse  was  killed 
and  examined  post-mortem.     The  auto])sy  revealed  the  j^resence  of  an 


16  EXPERIMENTS    WITH    INFECTED    MILK. 

even  distribution  of  the  lani])black  in  the  hni^^  and  no  trace  of  the  sub- 
stance in  any  other  portion  of  the  body.  The  ])articles  of  himp])lack 
in  some  portions  of  tlie  hni<;  Avere  very  fine  and  could  not  be  seen  with- 
out niao;nification. 

Similar  evidence  of  the  property  of  the  lun<i:  to  filter  the  ])lood  has 
been  observed  in  tlie  various  intravenous  injections  of  tubercle 
bacilli  into  cattle  that  have  been  made  from  time  to  time  at  the  Ex])eri- 
ment  Station.  Dead  tubercle  ijerms  or  tubercle  o;erms  of  a  virulence 
too  low  to  cause  a  profjressive  tuberculous  disease  when  injected  into 
the  veins  of  cattle  invariably  lodge  in  the  luno;  and  nowhere  else 
where  it  has  been  possible  to  discover  them,  and  cause  a  miliary  tuber- 
culosis from  which,  if  the  germs  are  either  dead  or  very  attenuated, 
recovery  is  slowly  made. 

SPREAD    OF    INFECTION    TO    OTHER    ORGANS. 

Next  to  the  lung  the  organ  most  frequently  affected  is  the  liver, 
which  was  affected  in  11  cases  out  of  12,  and  in  6  of  these  cases  it 
is  the  onl}^  organ  in  addition  to  tlie  lung  in  which  the  affection  had 
made  its  appearance.  Following  its  appearance  in  the  liver  we  find 
the  disease  spreading  with  equal  rapidity  to  the  spleen,  portal  lymph 
glands,  and  bronchial  lymph  glands,  and  from  then  on  a  tendency  to 
ra]iid  generalization  is  shown. 

If  the  disease  in  the  liver  followed  that  in  the  lung,  which  is  almost 
certain  in  the  twelve  injections  with  which  we  are  dealing,  it  is  more 
likely  to  have  received  the  infectious  material  from  the  lung  than 
from  the  seat  of  the  inoculation.  Infectious  material  from  the  lung 
we  believed  entered  the  circulation  through  the  pulmonary  veins  and 
was  carried  in  the  blood  to  the  heart  and  thrown  into  the  arterial  cir- 
culation and  filtered  out  when  the  l)lood  reached  the  liver,  the  jiecu- 
liar  circulation  of  which  may  specially  enable  it  to  act  as  a  very 
efficient  natural  filtering  system. 

REMARKS    0.\    THE    IKMi    INOCULATIONS. 

There  are  some  facts  that  must  be  kept  in  mind  in  estimating  the 
practical  significance  of  the  course  followed  by  the  tuberculous  disease 
in  this  group  of  hogs.  First,  the  affection  was  produced  by  the  intro- 
duction of  a  number  of  bacilli  vastly  greater  than  is  likely  to  occur  with 
a  natural  exj)osure;  hence  the  number  of  individual  original  foci  of 
disease  that  developed  simultaneously  was  vastly  greater  than  from  a 
natural  infection.  Second,  there  is  a  condition  known  as  immunity 
to  tuberculosis  that  can  be  jiroduced  by  either  the  intravenous  or  the 
subcutaneous  injecticm  of  tu})ercle  ])acilli  of  a  pathogenic  virulence 
somewhat  less  than  is  required  to  cause  an  active,  progressive  tuber- 
culosis. 

The  first  fact  j)robably  caused  the  j)resence  of  many  more  germs  in 
the  blood  of  the  hogs  at  all  times  after  the  inoculation  than  occurs  in 


NEW    SIGNIFICANCE    OF    LUNG    INFECTION.  17 

the  case  of  a  naturally  acquired  tuberculosis,  and  a  dej^osition  of  these 
germs  first  of  all  in  the  lung,  then  in  the  liver,  then  in  the  spleen,  and 
later  in  other  structures,  from  which  they  were  taken  up  hy  the  lymph 
glands. 

In  a  naturally  acciuired  tul)erculosis,  that  begins  with  possii)ly  one 
or  two  or  at  most  a  few  foci  of  disease  in  one  organ,  the  other  organs 
of  the  body  have  time  to  acquire  some  immunity  similar  to  that 
referred  to  as  the  second  fact.  Such  imnmnity  woukl  play  a  very 
small  ])art  in  protecting  the  organs  of  the  inoculated  ])igs,  because  of 
the  intense  character  of  the  exposure  and  the  rapid  sjiread  of  the 
disease.  We  have  in  the  hogs  a  strictly  acute  tid)erculosis,  and  wish 
to  distinguish  this  from  the  chronic  form  in  which  the  affection  is 
usually  encountered  in  nature  among  men  and  other  animals.  This 
probably  explains  the  absence  of  lymph-gland  disease  in  8  of  the  12 
hogs.  In  the  acute  disease  we  have  the  distril)Ution  of  infectious 
material  going  on  through  the  circidation:  in  the  chronic  disease  we 
have  the  increase  progressing  about  the  ])eripheral  ])ortions  of  each 
focus  and,  because  of  their  incessant  exjiosure,  an  early  afiection  of 
the  lymph  glands  that  first  receive  the  drain  from  the  tissues  in  which 
the  lesions  are  located;  and  when  in  the  chronic  disease  an  occasional 
bacillus  is  carried  by  the  blood  to  the  liver  or  spleen  the  acquired 
resistance — the  immunity  that  may  be  caused  in  some  organs  ])y  the 
presence  of  tuberculosis  in  other  organs — prevents  the  development 
of  fresh  disease  in  most  instances.  This  view  receives  some  sui)port 
from  the  fact  that  animals,  for  example,  with  extensively  tubercidous 
lungs  swallow  an  amount  of  infectious  material  many  times  greater 
than  healthy  animals  can  obtahi  anywhere  on  natural  ex})osure 
without  necessarily  causing  tuberculous  disease  of  the  throat  glands 
or  abdominal  organs.  The  ingestion  of  infectious  material  is  evi- 
dently nuicli  more  dangerous  to  healthy  animals  than  to  the  still 
unaffected  organs  of  animals  already  afi'ected  with  tuberculosis,  and 
if  the  records  of  the  guinea  ])igs  in  the  first  ])ortion  of  this  article  have 
any  value  they  show  that  higested  tu])erculoiis  material  is  more  apt 
to  cause  disease  of  the  throat  and  lungs  than  of  any  structure  con- 
tained in  the  al)dominal  cavity. 

NKW    SICMFICANCE    OF    LIXC    INFECTION. 

The  supposition  that  tui)erculosis  of  the  lung  is  commonly  due  to 
respired  infection  is  shown  to  be  unnecessary  to  account  for  the  ])res- 
ence  of  the  di-sease  more  frequently  in  the  lung  than  in  other  |)orti()ns 
of  the  body.  The  lung,  it  seems,  is  most  commonly  affected  simj)ly 
because  the  lymph  collected  from  all  ])orti()ns  of  the  body,  after  it 
reaches  the  blood  circulation,  nuist  ])ass  through  the  lung  before  it 
reaches  any  other  organ,  and  the  lung  evidently  will  not  admit  of  the 
passage  of  solid  particles,   other  than  the  elastic  blood   corpuscles. 


18  EXPERIMENTS    WITH    INFECTED    MILK. 

through  its  fihering  net  of  capillaries.  The  result  is  that  it  makes  no 
difference  at  what  point  the  tuberculous  material  enters  the  body 
there  is  nothing  to  protect  the  lung  from  infection  but  the  lymph 
glands,  and  that  the  lymph  glands  frequently  allow  tuberculous 
material  to  pass  through  them  or  by  them  without  becoming  affected 
is  conclusively  shown  l)y  the  series  of  hog  inoculations. 

The  inoculations  of  the  hogs  were  superficial — in  the  middle  of  the 
abdominal  region — and  the  lung  was  affected  in  100  per  cent  of  cases, 
and  in  only  25  per  cent  of  cases  was  any  disease  present  in  the  lymph 
glands  in  any  portion  of  the  thoracic  cavity.  In  58J  per  cent  of  cases 
the  disease  was  confined  entirely  to  the  lung  and  liver,  without  disease 
of  any  lymph  gland  in  the  body. 

Of  course  there  ma}"  be  some  difference  between  the  anatomical 
structure  of  the  lymph  glands  of  hogs  and  other  animals  of  a  kind 
that  will  allow  the  easier  passage  of  bacteria  through  the  former, 
and  likewise  similar  differences  in  the  structure  of  the  lymph  glands 
located  in  different  portions  of  the  body  of  the  same  animal.  But 
that  does  not  greatly  militate  against  the  conclusion  that  the  lung 
is  more  directlv  exposed  to  tuberculous  affection,  respired  affection 
left  out  of  consideration,  than  any  other  organ. 

Respired  infectious  material  comes  to  rest  in  the  limg  on  the 
mucous  surface  of  the  bronchial  tubes  and  is  then  still  located  on 
what  may  be  regarded  as  one  of  the  exterior  surfaces  of  the  body.  In 
this  location,  because  of  the  irritation  produced  by  the  material  with 
which  it  gains  entrance — dust,  etc. — it  has  an  excellent  chance  to 
become  enveloped  with  mucous  secretions  and  to  be  coughed  up  and 
either  swallow^ed  or  expectorated.  This  consideration,  taken  in  con- 
nection with  the  facts  w^e  have  presented  to  account  for  the  more 
frequent  presence  of  the  disease  in  the  lung  than  elsewhere,  seems  to 
show  that  tuberculosis  due  to  bacilli  that  enter  the  lung  with  the 
breathed  air  is  an  uncommon  affection.  If  this  conclusion  is  true, 
its  practical  significance  lies  in  the  caution  to  be  doubly  sure  that  our 
food  and  drink  is  free  from  tubercle  germs,  and  especially  that  it  is 
wise  to  avoid  the  use  of  the  milk  produced  by  tuberculous  cows  or  in 
stables  containing  tuberculous  cattle. 

RESISTANCE  OF  TUBERCLE  GERMS. 

The  tubercle  bacillus  is  a  peculiar  organism  in  its  conduct  in  the 
animal  body,  independent  of  its  real  pathogenic  significance.  When 
cultures  of  other  bacteria  are  injected  into  the  body  of  an  animal 
insusceptible  to  the  affection  of  which  the  germs  in  question  may  be 
the  s])ecific  cause,  these  germs  or  bacteria  disappear  entirely  from 
the  body  in  a  A-ery  short  time.  The  same  is  not  true  of  the  bacillus 
of  tuberculosis;  on  the  contrary,  it  shows  an  enormous  resistance 
to  the  destroying  and  annihilating  jirocesses  that  are  brought  to  bear 


SUMMARY.  19 

against  it  by  the  body.  Even  dead  or  sterile  cultures  of  tubercle 
bacilli  injected  into  cattle  or  sheep  remain  lodged  in  the  tissue  for 
months  and  years  in  a  manner  in  which  their  presence  can  be  micro- 
scopically demonstrated. 

SUMMARY. 

To  sum  up,  we  believe  the  experiments  presented  have  shown  the 
following  facts : 

1.  That  the  high  susceptibility  of  guinea  pigs  to  tuberculosis  holds 
good  only  when  the  infectious  material  is  introduced  into  the  body 
in  a  way  in  which  it  can  not  escape  through  the  natural  excretory 
organs;  that  is,  when  it  is  injected  under  the  skin,  into  the  abdominal 
cavity,  into  the  veins,  into  the  thorax,  ^tc. 

To  strengthen  this  conclusion,  we  may  add  that  we  recently  exj^osed 
52  guinea  pigs  and  6  hogs  to  tuberculosis  through  milk  feeding,  the 
milk  given  the  guinea  pigs  and  the  hogs  being  indentical  in  its  infec- 
tious character.  The  result  was  that  5  of  the  6  hogs  contracted 
tuberculosis  and  the  52  guinea  pigs  remained  unaffected  and  in 
perfect  health.  A  more  detailed  report  of  this  experiment  will  be 
published  at  another  time. 

2.  That  the  localization  of  tuberculous  disease  in  the  lung  of  an 
animal  gives  us  no  information  as  to  the  point  at  which  the  infectious 
material  entered.  • 

3.  That  the  lung  is  more  especially  and  directly  exposed  to  tuber- 
culous affection  than  any  other  organ,  because  of  the  character  of  its 
circulation  and  because  the  entire  lymph  stream  that  is  poured  into 
the  circulation  must  pass  through  the  lung  before  it  reaches  tlie  capil- 
lary structures  or  smaller  and  finer  vessels  of  any  other  organ. 

4.  That  it  is  not  necessary  to  account  for  the  great  frequency 
with  which  tuberculosis  localizes  itself  in  the  lung  by  suj^posing  that 
the  most  common  form  of  exposure  to  tuberculosis  is  through  the 
respiration. 

5.  That  the  experiments,  taken  as  a  whole,  direct  special  attention 
to  the  danger  sustained  through  exposure  to  tuberculous  material 
that  enters  the  body  with  the  food.  This  fact  can  not  be  too 
strongly  emphasized. 

o 


I 


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New  Y'otk,  N.  Y.— Dr.  W.H.  Rose,  18  Broadway. 
Norfolk,  Va.— Dr.  Q.  C.  Favllle,  P.  O.  box  7%. 


Philadelphia.  Pa.— Dr.  C.  A.  Schaufler,  134  South 
Soconu  stnvt. 

Portland,  Me.— Dr.  F.  W.  Huntington,  U.  S.  cus- 
toms office.  Grand  Trunk  R.  R.  wharf. 


INSPECTION    AND    QUARANTINE    OF   IMPORTED    ANIMALS. 


Qu(vtantin^  stations. 


Athenia,  N.  .1.  (for  the  port  of  Now  York). — Dr. 

G(?orge  W.  Pope,  superinUnident. 
llalethorp,  Md.   (for  the  port  of   Baltimore).- 

William  II.  Wade,  superintendent. 


Littleton,  Mass.  (for  th<!  ]wrt  of  Boston). — Dr. 
J.  F.  Ryder,  inspector  in  charge,  141  Milk  street, 
Boston,  Mass. 


Inspectors  on  the  Canadian  border. 


Calais,  Me.— Dr.  II.  T.  Potter. 

Carthage,  N.  Y.— Dr.  W.  S.  Corlis. 

Detroit.  Mich. — Dr.  L.  K.  Green,  care  Hammond, 

Standish  &  Co. 
Fort  Fairfield,  Me.— Dr.  F.  M.  Perry. 
Malone,  N.  Y.— Dr.  11.  D.  Mayne. 
Newport,  Vt.— Dr.  G.  W.  Ward. 


Ogdcnsburg,  N.  Y.— Dr.  Charles  Cowie. 
Orono,  Mo.— Dr.  F.  L.  Rus.soU. 
Port  Huron,  Mich.— Dr.  David  Cununing,  912  La- 
peer avenue. 
St.  Albans,  Vt.— Dr.  C.  L.  Morin. 
Sault  Ste.  Marie,  Mich.— Dr.  J.  F.  Dcadman. 


Inspectors  on  the  Mexican  border. 


El  Paso,  Tex.- Dr.  Thomas  A.  Bray. 
San  Antonio,  Tex.— Dr.  Joseph  W.  Parker. 


San  Diego,  Cal.— Dr.  Robert  Darling,  care  Charles 
S.  Hardy. 


VETERINARY    1NSPECTX)RS    STATIONED   ABROAD. 


Dr.W.  ll.Wray,  34  Streatham  Hill,  London,  S.W., 
England,  in  charge  for  Great  Britain  and  Ire- 
land. 


Dr.  T.  A.  Gcddcs,  caro  U.  S.  consulate,  Loudon, 

England. 
Dr.  V.  A.  Norgaard,  Honolulu,  Hawaii. 


DAIRY   INSPECTORS. 


M.  W.  Lang,  room  423  Marine  Building,  Chicago, 
111. 

Robert  McAdam,room  423  Marine  Building,  Chi- 
cago, 111. 


E.  A.  McDonald,  Seattle,  Wash. 

Levi  Wells,  Laceyville,  Pa. 

G.  M.  Whitaker,  Washington,  D.  C. 


Universit 
Southe 
Libra 


